The Electrocardiographic Leads
As noted in Chap. 1, propagation of the electrical stimulus in the heart can be represented as dipoles. For simplicity’s sake, each dipole is represented as a vector with a negatively charged tail and a positively charged head (Fig. 2.1). ECG electrodes are attached to the surfaces of specific body areas and connected to one another to form leads. The electrical potentials in the heart are recorded by the leads and transmitted them to the electrocardiograph, which is a galvanometric recording device (Fig. 2.2). Vectors travelling away from the recording point are represented by negative deflections; those moving toward the recording point appear as positive waves (Fig. 2.3).